I am no expert...
By: blomman Mr Blue : June 25th, 2012-14:30
Hi OC, Very nice PW - you should send it to the manufacture for a SPA treatment! I am no expert, but from the looks of the bridges and the swan neck regulatur it looks to be the Cal 20 1/2'" or 20 1/2'" N.V.S.I. Sorry, but I don't know what the letters ar...